1. Field of the Invention
The present invention relates to a fence structure that may reinforce the combination strength of the fence assemblies to keep steady even under being exerted a pulling or pushing force, and allows the angle of the transverse railing and the vertical picket to be adjustable.
2. Description of the Prior Art
As disclosed in U.S. Pat. No. 7,384,025, the prior art fence assembly provides a screw hiding device for combining lateral tubes with upright tubes. The screw hiding device includes a position strip arranged inside the lateral tube. By such an arrangement, the screws and the position strips are allowed to be hidden to beautify the appearance of the fence structure.
An alternative prior art fence assembly disclosed in U.S. Pat. No. 8,413,965 comprises a plurality of vertical pickets which have at least one pivot hole formed therein, a plurality of rails which extend transversely to the vertical pickets and whose top wall provides a plurality of picket openings corresponding to the plurality of vertical pickets to receive the plurality of vertical pickets, and one or more boss strips which are arranged transversely to the side of the vertical picket providing the pivot hole. The boss strip includes a protruding structure corresponding to the pivot hole, and the protruding structure is received inside the pivot hole to allow the boss strip and the vertical picket to rotate pivotally according to needs. The boss strip is arranged between the rail and the vertical picket to hold the rail to avoid sliding down, as shown in FIG. 4 of U.S. Pat. No. 8,413,965. The outer wall of the protruding structure of the boss strip disclosed in U.S. Pat. No. 8,413,965 is a conical surface, such that the rail and the boss strip can only rotate pivotally when the protruding structure is inserted inside the pivot hole. However, the boss strip can not prevent axially-slipping. Hence, the protruding structure whose outer wall is a conical surface will slip easily out of the pivot hole to cause the transverse rail to displace or unfasten when the fence rail or the vertical picket is pushed or pulled by exterior forces. Therefore, the aforesaid structure needs to be improved.